Autolysis and Rancidity Development in Tropical Freshwater Fish Viscera during Fermentation

Ahrned, Javeed and Mahendrakar, N. S. (1996) Autolysis and Rancidity Development in Tropical Freshwater Fish Viscera during Fermentation. Bioresource Technology, 58. pp. 247-251.

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Abstract

To develop an ensiling process to preserve the nutrients in fish viscera, the offal was homogenised with 10% (w/w) molasses. Propionic acid (0.5% v/w) was added as an antimycotic agent. NaCI (2% w/w) and ethoxy- quin (0.02% w/w) were added to see the effect on autolytic changes and rancidity development, respec- tively. Fermentation was carried out under microaerophilic condition at 26+2°C. Total volatile nitrogen, non-protein nitrogen, alpha-amino nitrogen (autolytic changes) and free fatty-acid content increased (P <O.O01) rapidly during the first 4 days and then remained constant up to 8 days. Salt had no influence on autolysis. Peroxide value (PV) increased (P<O.O01) initially up to 3-4 days and then decreased. A rapid increase (P <0.001) up to 2 days and small (P>O.05) subsequent increase in iodine value (IV) were observed. Thiobarbituric acid (TBA) number increased linearly up to 8 days of fermentation period. Ethoxyquin was effective in controlling oxida- tive rancidity, as indicated by significantly (P <O.O01) lower PVs and TBA numbers and higher IVs. Copy- ated (Hassan & Heath, 1986). Fermentation ensiling seems to be a more economical process compared to acid ensiling, as the latter requires expensive acids. Hence, in order to develop a fermentation ensiling process for the preparation of silage from fish viscera this work was undertaken. Our earlier studies indicated that a minimum of 10% molasses is required to effectively ferment fish viscera (Javeed Ahmed & Mahendrakar, 1995) and a microbiolog- ically stable silage product can be obtained by further treating viscera with 0.5% propionic acid (Javeed Ahmed et al., 1995). Chemical changes in fermentation ensiling have not been studied as much as in acid ensiling (Raa & Gildberg, 1982). Autolytic changes and rancidity development which may affect the nutritional quality of fish-viscera silage are reported in the present paper.

Item Type:	Article
Uncontrolled Keywords:	Fish viscera, fermentation, silage, chemi- cal changes, autolysis, rancidity.
Subjects:	600 Technology > 05 Chemical engineering > 04 Fermentation Technology 600 Technology > 08 Food technology > 28 Meat, Fish & Poultry
Divisions:	Meat Fish and Poultry Technology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	19 Aug 2008 09:37
Last Modified:	28 Dec 2011 10:05
URI:	http://ir.cftri.res.in/id/eprint/8730

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